Method



W. R. WEBSTER.

METHOD OF-MAKING BRASS AND SIMILAR ALLOYS.

APPLICATION FILED MAR. 31. I920.

Patented Aug. 22, 1922.

nvewboz Maw RM! PATENT OFFICE.

WILLIAM R. WEBSTER, OF BRIDG-EPORT, CONNECTICUT.

METHOD OF MAKING" BRASS AND SIMILAR ALLOYS.

Specification of Letters Patent.

Patented Aug. 22, 1922.

Application filed March 31, 1920. Serial No. 370,221.

To all whom it may concern:

Be it known that I, l VILLIAM R. Wn'ssrnn, a citizen of the United States, lBSldlIlQ, in

Bridgeport, county of Fairfield, and State of Connecticut, have invented certain new and useful Improvements in Methods of Making Brass and Similar Alloys, of which the following is a full, clear, and exact description.

In making brass, the utilization of scrap is common practice, and in many cases the charge of metal introduced into the furnace for melting and subsequent casting contains a large percentage of scrap brass. For convenience in casting the brass ingots, the furnaces are preferably of the tilting type. The best results have been secured with. tilt ing electric induction furnaces of the kind wherein a secondary consisting of a part of the molten metal of the charge is located below the main body of the charge or bath, and is so arranged as to promote and maintain the circulation of the whole charge by motor effect. An ehicient type of furnace for the purpose in question is shown, for ex ample, in the Clark Patent, No. 1,828,712, of January 20, 1920.

The development of the electric furnace has progressed to such a stage that tl e proper temperatures for the melting of brass and similar scrap can be produced and maintaincd without difficulty. There has been -ulty, however, as regards the maintenance of a constant mixture,that is to say, a constant ratio of metals such as copper and zinc in the resulting product. This is due to the fact that the brass scrap available in. the market has in its composition a varyingand uncertain percentage of copper and spelter. lVhere large amounts of this material are melted in brass furnace, considerable trouble is experienced in determining its composition by ordinary methods, because different portions of a particular lot or quantity will have different compositions.

It is, of course, entirely possible to melt such scrap in a furnace, draw a sample of molten metal from the furnace, and hold the charge molten in the furnace until the com JOSltlOii of the santiple has been determined by chemical analysis. The necessary a of copper or nine can then he adds charge, so that the resultant mixture will be what .is desired. To make such a chemical analysis, however, requires in almost all cases not less than half an hour, usually more. It will be understood, therefore, that, as furnaces employed for this work are capable of melting a charge in about one hour, the method just referred to (involving, if practised the necessity for holding the fur nace idle for about half the time, with the consequent loss of furnace capacity and expenditure of heat) is very expensive. This method is, in fact, so inconvenient and expensive that it is not employed under ordinary circumstances. 1

Que of the primary objects of my invention is to overcome these drawbacks by providing a method whereby the composition of the brass or similar alloy may be quickly but accurately determined, so that a constant mixture in the furnace product may be maintained in a commercially practicable manner.

Another object of the invention is to provide method of producing castings of a uniform mixture from niiiscellaneous or ther scrap without undue loss of furnace output.

To these and other ends, the invention conin the novel features and procedure to be l'iereinafter described and claimed.

In the accompanying drawing, 1 have shown a h aiirlness curve which may be used conveniently in the practice of my new method.

It is well known that certain physical properties of brass and similar alloys vary with the percentages of the elements, e. copper and zinc, of which the alloy is composed. These physicalproperties or characteristics include tensile strength, percentage of elongation, hardness, electrical resistance, etc. I have found that by accurately determining the variation in physical properties corresponding to varying; per centages of copper and Zinc in brass, for example, and expressing this relation in the form of a curve or table of corresponding values, it is possible by determining one of the physical values of a brass of unknown composition, to determine its composition by reference to the above mentioned curve or dole of v lues, and that by utilizing the ini ati hus derived, in the manner hereinafter set forth, a valuable improvement in a considerable range.

the method of making brass and similar alloys may be obtained.

In carrying the invention into practice, my preferred procedure -is as follows:

Samples of brass are procured, wherein the In this formula, L is the load in kilograms under which the ball is pressed into the material; A is the spherical area of: the impression made by the ball, in square millimeters; and Itis the radius ofthe ball, 6X- pressed in i'nillimetei s. i I 1 In the preferred practice or my invention, a steel ball of accurately known diameter is pressed into each sample by the application of a measured, force as in the Brinell test; but inorder to save computation, a standard sized ball and a standard load are used in each instance, whereby a measurement of the impression of the ball gives all the information required. l?relierably, the diameter of the impression is measured, and this can be done very accurately by the use of a 1nicrometer microscope. A table is then prepared or a curve plotted, indicating the variation of the diameterso'f the impressions of the different samples, which diameters have been found to be proportionate to the copper content ol the respective samples. The accompanying drawing shows such a curve where the abscissa represents, for example, the copper content, in per cent, and the ordinate represents, for example, the

diameter of the ball impression inmillimeters.

In manufacturing brass of a predeters mined composition, where there is a fairly large percentage of scrap 1n the charge, I

draw a sample from the molten charge and cool it. I then test it by the ball impression test and compare the result with the result of the tests of the samples of accurately known composition, as shown, for instance, by the curve above mentioned. It, for example, the diameter of the impression in the sample unknown composition is 3.5%, I lin a l. the point where lies on the ordinate of tire charge, which hasbecnpreviously determined, the amount of copper or zinc which it is necessary to add to bring the charge to the desired composition, and such addition is then made. i

The test preferred to can be made'in apnrmimately live minutes, and it will be seen, therefore, that the practice of the in.- vention overcomes the necessity of holding the furnace idle for a long period.

Another feature of great importance is the accuracy of determination which is possible by my new method in such a short time. The composition of the alloy ormixture can be determined most cases within one-half of oneper cent of the exact figure, whereas in 'ljormer ordinary commercial practice it was diliicult to keep the content of a given elementwithinfrom three to four per cent or? that desired. H

Various changes may be made in the detailed procedure herein particularly described without departure from the scope of my invention as defined in the claims.

In the preferred practice of the invention, owing to the ii act that the electric furnace is not emptied completely when. it is poured, there is a certain residual charge, which tends neutralize to 'a certain degree any variation in i'nixture in the succeeding charge. Also, the composition of the scrap ea]. be predicted with considerable certainty in some cases, as where the scrap is being taken from a certain part of a car-load lot for example. Under these conditions, it will not be necessary to hold the charge molten in the furnace while a test is being made. i l-l ter casting a charge and making a test thereof in. the manner previously described,

From this intersection I the necessary correction in mixture can be i made in the next charge and so on succes sivel'. On the other hand there are nu- .merous cases where the. identification of the crap is not at all good and where it is advisable to hold the charge while the test is being made and to change the composition of that particularcharge, it necessary. It is to be understood, therefore, that when referr ce is made herein to the addition to the charge in the furnace of suflicient copper or zinc to bring the materialto the desired composition, this is not to be understood as meaning the particular charge of which the test was made, but may refer to that or another charge. I v

tlliwinusly, also, the improved. method is applicable to the manufacture of alloys or mixtures other than those containing copper and zinc, and if carried out in connection with the manufacture of brass, the same is applicable to a determination of the content of metals other than copper and zinc, occurring either intentionally or as undesirable impurities.

What I claim is:

l. The method of making brass from scrap, which comprises a determination of a value of a physical characteristic of each of a plurality of samples of brasshaving varying known proportions of copper and zinc, determining a comparable value of the same physical characteristic of a sample of brass drawn from a molten furnace charge containing scrap brass, comparing those values to determine the composition of the last mentioned sample, and then adding to the charge of metal in the furnace suflicien't copper or zinc to bring the mixture to the composition desired.

2. The method of making brass or similar alloys, which comprises first ascertaining the composition of the allow while in the molten stage of its preparation, by determining the value of a physical property and comparing such value with those of similar alloys of known composition, and then in the light of the obtained information, altering the molten alloy to obtain the desired composition.

3. The method of making brass and similar alloys, which comprises melting a charge consisting at least partly of scrap metal, ascertaining the composition of the alloy while in the molten stage of its preparation by withdrawing a sample from the furnace, determining the value of a physical property of such sample, and comparing such value with those of alloys of accurately known composition, and then in the light of the obtained information, altering the furnace charge to obtain the desired composition.

4. The method of making brass, where a charge containing brass scrap is melted for casting, which comprises, first, a determina tion of the relative hardness of a number of brass samples of known composition having a successively increasing copper content, drawing a sample from the molten metal in the furnace, testing such sample for hardness, comparing the hardness of such sample with those of the above mentioned samples to determine the relative composition of the sample drawn from the furnace, and then adding suflicient copper or zinc to the charge to bring the copper and zinc contents to the desired proportions.

5. The method of making brass, which comprises melting in a suitable furnace a charge containing scrap brass, ascertaining the composition of the resulting alloy while in the molten stage of its preparation by measuring the value of a physical property thereof, and comparing such value with those of brass samples of accurately known composition, and then in the light of the obtained information altering the proportions of the furnace charge to obtain the desired composition thereof.

6. The method of making brass or a simi lar alloy wherein a charge containing scrap is melted in a suitable furnace for subsequent casting, which comprises ascertaining the composition of the furnace charge by withdrawing a sample of molten metal, permitting it to cool, measuring the value of a physical property of the sample, comparing such value with those of alloy samples of accurately known composition, and then in the light of the obtained information alteringthe furnace charge so as to bring about the desired proportioning of. the metals therein.

7. The method of making brass, wherein a charge containing brass scrap is melted in a furnace for casting, which comprises a determination of the hardness ofa number of samples of brass of known, different composition by ball impression tests, plotting a curve in respect to said samples, drawing a sample from the molten metal in the furnace, testing it by ball impression to determine, by reference to the above mentioned hardness curve, the percentage of copper in such sample, and then adding copper or zine to the char e as required.

8. The method of controlling the composi tion of brass and similar alloys melted for casting, which consists in determining values of a given physical property of a number of samples of known, varying contents, testing the material of unknown composition to determine the value of the same physical prop erty thereof, comparing the value of such physical property with those of the above mentioned samples, and varying the compo-' sition of the casting charge as desired.

9. The method of controlling the composition of brass and similar alloys melted for casting, which consists in determining a given physical characteristic of a number of alloy samples of accurately known composition, said samples presenting a series having a successively increasing content of one metal, recording the variation in the value of such characteristic in the different samples, testing by a relatively rapid physical test the alloy of unknown composition to determine the value of the aforesaid physical characteristic thereof, comparing such value with the record of the correspondingvalues of the samples, and varying the casting charge to bring it to the desired composition.

10. The method melting brass for east-- ing, where at least a portion of the cha k a consists of soup and where the charge is melted in a suitable furnace, which cornprises the measurement of a given physical Ell characteristic of various samples of brass of accurately known but varying composition, recording such. measurements as a series indicating a progressive increase in the content of a given component of the alloy, testing a piece of metal which has been melted in the furnace so as to measure the aforesaid physical cha 'acteristic thereof and determine its relation to the series of samples in respect to such physical characteristic, to determine thereby its relative composition, and then varying the charge in the furnace to bring it to the desired composition.

11. The method of melting brass for casting where the charge is melted in a furnace,

which consists in testing by ball impression the hardness of a number of brass samples of known but varyingcomposition having a progressively increasing content of one of the metal components of the alloy, expressing and recording the hardness of such samples in a series, testing by ball impression the-hardness of a brass piece of unknown composition which has been melted in the .25 furnace and has approximately the same temperature at which the samples were tested, and expressing such hardness in a com.- parable value, comparing such hardness 911" us with the record of the varying hardness of the samples so as to determine the composition of the piece of unknown composi tion, and thereafter varying the casting charge to bring it to the desired composition;

12. The method of melting metal for .35 casting, where thecharge is melted in a furnace, which consists in measuring a given physical characteristic of a metal of accurately known composition, drawing off from the molten metal in thefurnace a sample of metal whose composition is to be determined, testing such sample to measure the aforesaid physical characteristic thereof in comparison with the metal of known composition, and adding to the furnace charge the necessary material to bringthe charge to the composition desired.

13. In the art of melting metal for castiug, where a charge containing scrap metal is melted in a furnace, the method which ,50 consists in determining a given physical property value of a numberof metal samples of accurately known composition, testing when cold a piece of metal which has been melted'in the furnace to ascertainithe value of the aforesaid physical characteristic thereof in comparison with the values of the metal samples previously mentioned, whereby the composition of the charge is determined, and then adding the necessary material to bring the charge to the composition desired.

14. In the art of melting metal for easting, the method which comprises determin ing the hardness values of a number of metal samples of accurately known, differcal-characterist the values of the samples, whereby the com v ent composition, drawing off from the molten metal of the charge a sample, permitting the same to cool, then testing said sample for hardness and determining its hardness value in terms comparable to the first mentioned hm'dness values, whereby the composition of the charge in the furnace maybe ascertained, and then adding the necessary material to the charge to bring it tothe desired composition. 1

15.111 the art of meltingometal for casting, where a charge containing scrap metal is melted in a furnace, the method which comprises a determiimtion of the hardness values, by ball impression, of a number of samples of accuratel known, different com position, drawing oft from the molten metal in the furnace a sample, permitting it to cool, testing it by ball impression to deter mine its hardness value and thereby its composition in relation to those of the samples of known composition previously mentioned, and then varying the composition of the furnace charge as desired.

16. The method of melting metal for easting W'liGY-G the charge is melted in a furnace. which consists in testing by ball iuunrss on the hardness of a number of' sanugl oi. known but varying compositirm, measuring the diameters of the impressions in the various samples, recording such diameters in a progressive series, testing by ball imn-ession the hardness of a piece of metal that has been melted in the furnace, measuring the diameter of the impre 'sion in such metal. piece so as to determine its place relatively to the series of samples and thereby its com position, and then varying the charge in the furmive-to bring it to the desired composi tion.

17. In the artof melting metal for casting, the method which consists in determining the val ues of a given physical property of a number of metal sanu'iles of acciu'ately k1 awn composition, testing when cold, by a relatively rapid physical test, a piece of metal which h as been melted in the furnace, to ascertain the value of the aforesaid physithorcof in (:omparison with position of such piece, of metal is determined, and then varying the charge in the furnace to bring it to the desired composition. r

18. The method of making brass and similar alloys, which comprisesmelting in a suitable furnace a charge consisting at least partly of scrap metal, ascertaining the composition of the alloy while in the molten stage of its preparation by withdrawing a sample from the furnace, determining the hardness of the sample when'cooled, comparing such hardness with those of alloy samples of accurately known composition, and then by the aid of the information thereby obtained altering the molten alloy to obtain the desired composition thereof.

19. in the art of making alloys, the method of maintaining a constant mixture of metals in succeeding furnace charges, which consists in determining the values of a given plrysical characteristic of a number of alloy samples of accurately known but different composition, making a record of such values, testing from time to time a cooled piece of metal which has been melted in the furnace, to ascertain the comparable value of the aforesaid physical characteristic thereof. comparing such value with the aforesaid record so as to determine the composition of such piece of cooled metal, and then varying the charge as required to keep the mixture uniform.

20. In the u'iannfacturc of metallic alloys,

taining a substantially COIESJZUlt mixture in the furnace charge on repeated melting op erations, which consists in determining the values of a. given physical characteristic of a number o metal samples of similar alloys ha ing accurately known but different com position, preparing a record of such values a series, in which the content of one metallic component progressively increases, testing by a rapid physical test a cooled piece of metal which has been melted in the furnace, to ascertain the comparable value of its aforesaid physical characteristic, comparing such value with the aforesaid record to determine the composition of such cooled piece of metal, varying the furnace charge if necessary to bring it to the desired composition, and then repeating the test as above set forth from time to time in connection with different meltings, and varying the fur nace charges to maintain a constant mixture in continued operation of the furnace.

21. In the art of making brass and similar alloys, the method which consists in ascertaining the composition of an alloy while in the molten stage of its preparation by measuring while the furnace is in operation the value of a physical property of a cooled piece of metal withdrawn from the bath, comparing such value with those of similar alloys of accurately known composition, and with the aid of the information thus obtained, altering the proportions of the constituents of the bath to obtain an alloy of the desired composition, and then pouring off a portion of the molten metal into a mold.

22. The method of making brass and similar alloys, where a charge containing scrap metal is melted for casting, which comprises a determination and recording of the relative values of one or more given physical characteristics of samples of a similar alloy having accurately known composition but successively increasing contents of one metal, testing by a rapid. physical test a cooled piece of metal which has been melted in the furnace, to ascertain in comparable terms the value of its aforesaid physical char cteristic or characteristics, comparing such value with the record of the samples to determine the place of the tested piece in the series of samples and thereby the composition of the tested piece, varying the content of the furnace charge to bring it to a definite composition, and then repeating the test of a cooled piece of metal from time to time and comparing the result with the sample rec- 0rd, on different meltings, and varying the contents of the furnace charge as required to maintain an approximately constant mixture on repeated meltings.

23. In the art of making brass and similar alloys, where charges containing scrap metal are melted in a suitable furnace, the method which comprises ascertaining the composition of the alloy while molten in the furnace by determining the value of a physical property of a sample withdrawn from the furnace and cooled, comparing such value with those of similar alloys of accurately known composition, varying the furnace charge to bring it to the desired composition in the light of the information thus obtained, and then repeating the determination of the value of the said physical charac teristic of cooled pieces of metal withdrawn from the furnace and the comparison there of with the record from time to time and continuing the variation of the constituents of the furnace charge as required to main tain a substantially constant mixture in repeated operations.

24. In the art of making brass, where charges containing scrap metal are melted in a suitable furnace, the method of maintaining a substantially constant mixture in successive furnace charges, which comprises measuring the values of a given physical characteristic of a number of brass samples of accurately known composition, having different copper contents, preparing a record of such values, measuring from time to time the aforesaid physical characteristic of a piece of cooled metal which has been melted in the furnace, comparing such value with the record to determine the composition of such piece of cooled metal, and varying the contents of the charge, if necessary, subsequent to the tests so as to maintain a substantially constant mixture.

25. In the art of making brass, where charges containing scrap metal are melted in a suitable furnace, the steps of measuring and recording the values of a physical characteristic of a number of different brass samples of accurately known composition having successively increasing contents of copper, testing a cooled piece of metal which has been melted in the furnace to determine the value of the aforesaid physieal characteristic thereof and comparing it with the Sample record, to ascertain the composition of such cooled piece of metal, varying the furnace charge to bring it to the desired composition, and then repeating the measurement of said physical characteristicof a cooled piece of mletal and the comparison thereof With the record from time to time,

and varying the furnace charge as required 10 to maintain a substantially constant mixture.

In Witness whereof, I have hereunto set my hand on the1 9thday of March 1920.

WVILLIAM R. WEBSTER.

Witnesses:

M. A. 'IUTTLE A. B. LYFORD. 

